Many types of hazardous wastes or other waste materials are collected in drums, barrels, boxes, or other containers for long term storage. These containers of materials are often collected and stored pending a decision as to the appropriate disposal method for the materials. Very large quantities of some types of wastes have collected in storage because there has simply been no viable disposal alternative. This is particularly true for the vast quantities of mixed wastes which include halogenated hydrocarbons and other toxic materials mixed with high and low level radioactive materials, or nonhazardous materials that have been contaminated with hazardous and/or radioactive materials. Containerized wastes not only present the problem of disposing of the collected waste material itself, but also present the problem of either treating or disposing of the containers which have themselves become contaminated.
It is known that certain chemically active or reactant metals held as a liquid at elevated temperatures have the ability to chemically reduce organic compounds including hazardous compounds such as halogenated hydrocarbons. Suitable reactant metals include aluminum, magnesium, lithium, and alloys of these metals as described in U.S. Pat. Nos. 5,000,101, 6,069,290, and 6,355,857 to Wagner. The entire content of each of these prior patents is hereby incorporated in this disclosure by this reference. These liquid reactant metals chemically reduce organic molecules to produce mostly hydrogen and nitrogen gas, elemental carbon, char, and metal salts. Most metals mixed with the organic materials or bound up in organic molecules in the waste materials dissolve or melt into the liquid reactant metal. Low boiling point metals such as Mercury may go to a gaseous state and separate from the liquid reactant metal with other gases. Other metals alloy with the liquid reactant metal or separate from the liquid reactant metal by gravity separation.
A consistent issue in waste treatment processes utilizing a bath of a liquid reactant metal is ensuring sufficient contact between the liquid reactant metal and the waste material itself or intermediate compounds generated from initial reactions between the waste material and liquid reactant metal. Although in some cases, it may be desirable to control the reactions with the liquid reactant metal to prevent the feed material from being fully reduced, it is desirable in treating most waste materials to ensure sufficient contact with the liquid reactant metal to completely reduce the feed material. The problem of providing the required contact time is particularly acute with gaseous or volatile materials because such materials quickly separate from the liquid reactant metal and produce a bubble at the top of the liquid reactant metal container. The separated material must generally be forced again into the liquid reactant metal to allow the reduction reactions to continue, or more rapidly continue. U.S. Pat. No. 6,227,126 to Wagner is directed to an apparatus and process for treating gaseous and volatile material in a liquid reactant metal. In this system, the feed material is injected into a treatment chamber and the flow or passage of gasses and reactant metal through the reaction chamber is manipulated to mix the respective materials and ensure sufficient contact to completely reduce the gaseous materials.
U.S. Pat. No. 5,452,671 is directed to an apparatus and process for using a liquid reactant metal to destroy highly hazardous liquid and gaseous compounds, particularly materials used as chemical weapons or used to produce chemical weapons. This patent discloses treating a canister of hazardous materials by dunking the canister into a liquid metal bath and holding the canister under the surface of the liquid reactant metal. The patent discloses a unique dunking mechanism that forces gasses escaping from the submerged container to collect at different collection points within the liquid reactant metal and follow a tortuous path through the liquid reactant metal before reaching the uppermost surface of the reactant metal. Forcing gasses to follow this tortuous path through the various subsurface collection points was intended to provide the desired contact between the reactant metal and chemicals in the gas. Although this dunking arrangement may be suitable for many applications, there remains a need for an apparatus and process for treating containerized feed materials in a liquid reactant metal so as to ensure sufficient contact between the liquid reactant metal and the feed material/intermediate reaction products to allow the desired reduction reactions to proceed to completion.